package network;


import java.io.IOException;
import java.net.*;
import java.util.Scanner;

public class UdpEchoClient {
    private DatagramSocket socket = null; //先制定网关文件为空
    private String serverIp = "";
    private  int serverPort = 0; //端口号

    public UdpEchoClient(String ip,int port) throws SocketException {
        //客户端这边就是手动指定端口
        socket = new DatagramSocket();
        serverIp = ip;
        serverPort = port;
    }

    public void start() throws IOException {
        System.out.println("客户端启动!");
        Scanner scanner = new Scanner(System.in);

        while (true) {
            //1.从控制台读取数据,作为请求
            System.out.print("-> ");
            String request = scanner.next();

            //2.将请求内容构造成DatagramPacket数据报对象
            DatagramPacket requestPacket = new DatagramPacket(request.getBytes(),request.getBytes().length,
                    InetAddress.getByName(serverIp),serverPort);

            socket.send(requestPacket);

            //3.尝试读取服务器的相应
            DatagramPacket responsePacket = new DatagramPacket(new byte[4096],4096);
            socket.receive(responsePacket);

            //4.把相应拼接成字符串并显示出来
            String response = new String(responsePacket.getData(),0, responsePacket.getLength());
            System.out.println(response);

        }
    }

    public static void main(String[] args) throws IOException {
        UdpEchoClient client = new UdpEchoClient("172.0.0.1",9090);
        client.start();
    }
}


